David Heyman, producer of Chamber of Secrets, spoke to CBBC Newsround's Lizo Mzimba about the movie - and filling the part of Cho Chang!
What's the pressure like to deliver as a producer, after the first film was so successful?
Well, it's hard to imagine, but there is no pressure from the outside. The only pressure is what we put on ourselves.
We began shooting the second film on 19 November and prior to that we'd been shooting for five weeks so there was no time to rest.
The only pressure was that we put on ourselves, which was to make a good a film as possible, that we hoped would be better than the first.
I hope we've achieved that.
Were there some tough decisions to be made about what to leave in and what to take out?
Yes, inevitably, there were sequences that were left out.
I wish the Deathday party was in the film but it's not.
In a film that's two-and-a-half hours long you have to leave stuff out.
Jo's books get longer and longer so we're going to have to make tougher decisions as we go forward.
We made some tough decisions on one and two and I'm sure we'll have to make some tough decisions on three as well.
How closely did you work with Jo on this movie?
For the second film we were a little more on our own. She'd seen the first, she trusted us, and we were a little more assured and comfortable.
In the first we had to create a whole world.